PCI: Don't try to restore VF BARs (70675e0b) · Commits · 戴 / test

VF BARs are read-only zero, so updating VF BARs will not have any effect. See the SR-IOV spec r1.1, sec 3.4.1.11. Don't update VF BARs in pci_restore_bars(). This avoids spurious "BAR %d: error updating" messages that we see when doing vfio pass-through after ("vfio-pci: Move idle devices to D3hot power state"). [bhelgaas: changelog, fix whitespace] Signed-off-by:

Wei Yang <weiyang@linux.vnet.ibm.com> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -484,7 +484,7 @@ int pci_wait_for_pending(struct pci_dev *dev, int pos, u16 mask)
		}

		/**
		* pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
		* pci_restore_bars - restore a device's BAR values (e.g. after wake-up)
		* @dev: PCI device to have its BARs restored
		*
		* Restore the BAR values for a given device, so as to make it
		@@ -494,6 +494,10 @@ static void pci_restore_bars(struct pci_dev *dev)
		{
		int i;

		/* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
		if (dev->is_virtfn)
		return;

		for (i = 0; i < PCI_BRIDGE_RESOURCES; i++)
		pci_update_resource(dev, i);
		}

drivers/pci/setup-res.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,11 @@ void pci_update_resource(struct pci_dev *dev, int resno)
		enum pci_bar_type type;
		struct resource *res = dev->resource + resno;

		if (dev->is_virtfn) {
		dev_warn(&dev->dev, "can't update VF BAR%d\n", resno);
		return;
		}

		/*
		* Ignore resources for unimplemented BARs and unused resource slots
		* for 64 bit BARs.

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